The BMW Z4 3.5is - N54 - 340hp (E89 - 2009 - 2018) produces 340bhp and 450Nm in standard form. Our Stage 1 ECU tuning file raises output to 370bhp and 500Nm, a gain of 30bhp and 50Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.